Image coding method, image decoding method, image coding apparatus, image decoding apparatus, and image coding and decoding apparatus

ABSTRACT

The image coding method is used to code images to generate a coded stream. The image coding method includes: writing, into a sequence parameter set in the coded stream to be generated, a first parameter representing a first bit-depth that is a bit-depth of a reconstructed sample in the images; and writing, into the sequence parameter set, a second parameter which is different from the first parameter and represents a second bit-depth that is a bit-depth of an Intra Pulse Code Modulation (IPCM) sample in the images.

TECHNICAL FIELD

The present disclosure relates to image coding methods of coding imagesto generate a coded stream, and image decoding methods of decodingimages included in the coded stream.

BACKGROUND ART

In the H.264 standard (see Non-Patent Literature 1), image (includingvideo) coding typically comprises intra coding using spatial predictionmethods, and inter coding using temporal prediction methods.

Temporal prediction may be performed for a number of differentinter-coding block types, such as Inter 16×16, Inter 16×8, Inter 8×16,inter 8×8, inter 8×4, inter 4×8 and Inter 4×4, while spatial predictionmay be performed for a number of intra-coding block types, such as Intra16×16, Intra 8×8 and Intra 4×4. Intra Pulse Code Modulation (IPCM)blocks are one kind of intra coding blocks.

IPCM blocks are blocks of uncompressed image samples where raw luma andchroma samples are signaled in the coded stream. They are typically usedin the case when the entropy coder produces more bits compared to rawdata bits when coding a block of image samples. In general, IPCM blocksare coded as uncompressed data in the coded stream.

CITATION LIST Non Patent Literature

-   [NPL 1] ITU-T H.264 March 2010

SUMMARY OF INVENTION Technical Problem

However, there is a situation where IPCM blocks prohibit improvement ofcoding efficiency. A data amount of an IPCM block depends on a size ofluma and chroma bit-depth. As a bit-depth is greater, a data amount ofan uncompressed IPCM block is larger. Therefore, in the above situation,IPCM blocks prohibit improvement of coding efficiency.

In order to address the above, one non-limiting and exemplary embodimentprovides an image coding method and an image decoding method by whichcoding efficiency can be improved by using an adaptive bit-depth.

Solution to Problem

In one general aspect of the present disclosure for solving the aboveproblem, there is provided an image coding method of coding images togenerate a coded stream, the image coding method including: writing afirst parameter into a sequence parameter set in the coded stream to begenerated, the first parameter representing a first bit-depth that is abit-depth of a reconstructed sample in the images; and writing a secondparameter different from the first parameter into the sequence parameterset, the second parameter representing a second bit-depth that is abit-depth of an Intra Pulse Code Modulation (IPCM) sample in the images.

Thereby, it is possible to set the bit-depth for IPCM samples separatelyand independently from the bit-depth for reconstructed samples.Therefore, redundant data of the IPCM samples can be reduced. As aresult, coding efficiency can be improved.

Furthermore, the image coding method may include writing the IPCM sampleinto the coded stream at the second bit-depth.

Thereby, IPCM samples are written into the coded stream at the bit-depthset for IPCM samples which is different from the bit-depth set forreconstructed samples. As a result, coding efficiency can be improved.

Still further, the image coding method may further includereconstructing a sample at the first bit-depth from a coded sample inthe images, so as to generate the reconstructed sample.

Thereby, reconstructed samples are generated at the bit-depth set forreconstructed samples which is different from the bit-depth set for IPCMsamples. As a result, image quality can be improved.

Still further, in the writing of the second parameter, the secondparameter representing the second bit-depth that may be equal to orsmaller than the first bit-depth is written.

Thereby, the bit-depth for IPCM samples is set to be equal to or smallerthan the bit-depth for reconstructed samples. Therefore, redundant dataof the IPCM samples can be reduced.

Still further, the image coding method may further include convertingthe IPCM sample at the second bit-depth into the reconstructed sample atthe first bit-depth.

Thereby, even if the bit-depth for IPCM samples is different from thebit-depth for reconstructed samples, IPCM samples can be used asreconstructed samples.

Still further, in the writing of the second parameter, the secondparameter representing the second bit-depth that may be smaller than athird bit-depth is written, the third bit-depth being a bit-depth of anoriginal sample in the images, and the image coding method may furtherinclude converting the original sample at the third bit-depth into asample at the second bit-depth, so as to decrease the bit-depth of theIPCM sample corresponding to the original sample.

Thereby, it is possible to reduce redundant data of IPCM samplescorresponding to original samples. As a result, coding efficiency can beimproved.

Still further, in the writing of the first parameter, the firstparameter representing the first bit-depth that may be larger than athird bit-depth is written, the third bit-depth being a bit-depth of anoriginal sample in the images, and the image coding method may furtherinclude converting the original sample at the third bit-depth into asample at the first bit-depth, so as to increase the bit-depth of thereconstructed sample corresponding to the original sample.

Thereby, it is possible to increase the bit-depth of reconstructedsamples corresponding to original samples. As a result, image qualitycan be improved.

Still further, the image coding method may further include writing acoded sample coded using the reconstructed sample at the first bit-depthinto the coded stream.

Thereby, coded samples coded using reconstructed samples at thebit-depth for reconstructed samples are written to the coded stream.

In another aspect of the present disclosure, there is provided an imagedecoding method of decoding images in a coded stream, the image decodingmethod including: obtaining a first parameter from a sequence parameterset in the coded stream, the first parameter representing a firstbit-depth that is a bit-depth of a reconstructed sample in the images;and obtaining a second parameter different from the first parameter fromthe sequence parameter set, the second parameter representing a secondbit-depth that is a bit-depth of an Intra Pulse Code Modulation (IPCM)sample in the images.

Thereby, it is possible to set the bit-depth for IPCM samples separatelyand independently from the bit-depth for reconstructed samples.Therefore, redundant data of the IPCM samples can be reduced. As aresult, coding efficiency can be improved.

Furthermore, the image decoding method may further include obtaining theIPCM sample from the coded stream at the second bit-depth.

Thereby, IPCM samples are obtained from the coded stream at thebit-depth set for IPCM samples which is different from the bit-depth setfor reconstructed samples. As a result, coding efficiency can beimproved.

Still further, the image decoding method may further includereconstructing a sample at the first bit-depth from a coded sample inthe images, so as to generate the reconstructed sample.

Thereby, reconstructed samples are generated at the bit-depth set forreconstructed samples which is different from the bit-depth set for IPCMsamples. As a result, image quality can be improved.

Still further, in the obtaining of the second parameter, the secondparameter representing the second bit-depth that may be equal to orsmaller than the first bit-depth is obtained.

Thereby, the bit-depth for IPCM samples is set to be equal or smallerthan the bit-depth for reconstructed samples. Therefore, redundant dataof the IPCM samples can be reduced.

Still further, the image decoding method may further include convertingthe IPCM sample at the second bit-depth to the reconstructed sample atthe first bit-depth.

Thereby, even if the bit-depth for IPCM samples is different from thebit-depth for reconstructed samples, IPCM samples can be used asreconstructed samples.

Still further, in the obtaining of the second parameter, the secondparameter representing the second bit-depth that may be smaller than thefirst bit-depth is obtained, and the image decoding method may furtherinclude converting the IPCM sample at the second bit-depth into a sampleat the first bit-depth, so as to increase the bit-depth of the IPCMsample.

Thereby, even if the bit-depth for IPCM samples is different from thebit-depth for reconstructed samples, IPCM samples can be used asreconstructed samples.

Still further, in the obtaining of the second parameter, the secondparameter representing the second bit-depth that may be smaller than athird bit-depth is obtained, the third bit-depth being a bit-depth of anoriginal sample in the images.

Thereby, it is possible to appropriately obtain IPCM samples from whichredundant data is reduced. As a result, coding efficiency can beimproved.

Still further, in the obtaining of the first parameter, the firstparameter representing the first bit-depth that may be larger than athird bit-depth is obtained, the third bit-depth being a bit-depth of anoriginal sample in the images.

Thereby, it is possible to increase the bit-depth of reconstructedsamples. As a result, image quality can be improved.

Still further, the image decoding method may further include obtaining acoded sample to be decoded using the reconstructed sample at the firstbit-depth from the coded stream.

Thereby, it is possible to decode coded samples obtained from the codedstream, by using reconstructed samples at the bit-depth forreconstructed samples.

In still another aspect of the present disclosure, there is provided animage coding apparatus that codes images to generate a coded stream, theimage coding apparatus including: a first writing unit configured towrite a first parameter into a sequence parameter set in the codedstream to be generated, the first parameter representing a firstbit-depth that is a bit-depth of a reconstructed sample in the images;and a second writing unit configured to write a second parameterdifferent from the first parameter into the sequence parameter set, thesecond parameter representing a second bit-depth that is a bit-depth ofan Intra Pulse Code Modulation (IPCM) sample in the images.

Thereby, the image coding method is implemented as the image codingapparatus.

In still another aspect of the present disclosure, there is provided animage decoding apparatus that decodes images in a coded stream, theimage decoding apparatus including: a first obtaining unit configured toobtain a first parameter from a sequence parameter set in the codedstream, the first parameter representing a first bit-depth that is abit-depth of a reconstructed sample in the images; and a secondobtaining unit configured to obtain a second parameter different fromthe first parameter from the sequence parameter set, the secondparameter representing a second bit-depth that is a bit-depth of anIntra Pulse Code Modulation (IPCM) sample in the images.

Thereby, the image decoding method is implemented as the image decodingapparatus.

In still another aspect of the present disclosure, there is provided animage coding and decoding apparatus including an image coding unitconfigured to code images to generate a coded stream, wherein the imagecoding unit includes: a first writing unit configured to write a firstparameter into a sequence parameter set in the coded stream to begenerated, the first parameter representing a first bit-depth that is abit-depth of a reconstructed sample in the images; and a second writingunit configured to write a second parameter different from the firstparameter into the sequence parameter set, the second parameterrepresenting a second bit-depth that is a bit-depth of an Intra PulseCode Modulation (IPCM) sample in the images, and the image coding anddecoding apparatus further including an image decoding unit configuredto decode images in a coded stream, wherein the image decoding unitincludes: a first obtaining unit configured to obtain a first parameterfrom a sequence parameter set in the coded stream, the first parameterrepresenting a first bit-depth that is a bit-depth of a reconstructedsample in the images; and a second obtaining unit configured to obtain asecond parameter different from the first parameter from the sequenceparameter set, the second parameter representing a second bit-depth thatis a bit-depth of an IPCM sample in the images.

Thereby, the image coding apparatus and the image decoding apparatus areimplemented as the image coding and decoding apparatus.

Advantageous Effects of Invention

According to the present disclosure, it is possible to set a bit-depthfor IPCM samples separately and independently from a bit-depth forreconstructed samples. Therefore, redundant data of the IPCM samples canbe reduced. As a result, coding efficiency can be improved.

BRIEF DESCRIPTION OF DRAWINGS

These and other objects, advantages and features of the presentdisclosure will become apparent from the following description thereoftaken in conjunction with the accompanying drawings that illustrate aspecific embodiment of the present disclosure. In the Drawings:

FIG. 1 is a syntax diagram which shows the location of a field parameterin a coded stream;

FIG. 2 is a flowchart which shows a sequence of operations of an imagedecoding method H.264, Section 7.3.5;

FIG. 3 is a block diagram which shows a structure of an image codingapparatus according to Embodiment 1 of the present disclosure;

FIG. 4 is a syntax diagram which shows of 8-bit-depth conversionaccording to Embodiment 1;

FIG. 5 is a flowchart which shows a sequence of operations performed byan image coding apparatus according to Embodiment 1;

FIG. 6 is a syntax diagram which shows two field parameters in a codedstream according to Embodiment 1;

FIG. 7 is a block diagram which shows a structure of an image decodingapparatus according to Embodiment 2 of the present disclosure;

FIG. 8 is a flowchart which shows a sequence of operations performed bythe image decoding apparatus according to Embodiment 2;

FIG. 9 is a flowchart which shows a coding method of coding an imagebitstream according to Embodiment 3 of the present disclosure;

FIG. 10A is a block diagram which shows a structure of an image codingapparatus according to Embodiment 4 of the present disclosure;

FIG. 10B is a flowchart which shows operations performed by an imagecoding apparatus according to Embodiment 4;

FIG. 11A is a block diagram which shows a structure of an image decodingapparatus according to Embodiment 4;

FIG. 11B is a flowchart which shows operations performed by the imagedecoding apparatus according to Embodiment 4;

FIG. 12 is a block diagram which shows a structure of an image codingapparatus according to Embodiment 5 of the present disclosure;

FIG. 13 is a flowchart which shows operations performed by an imagecoding apparatus according to Embodiment 5;

FIG. 14 is a block diagram which shows a structure of an image decodingapparatus according to Embodiment 5;

FIG. 15 is a flowchart which shows operations performed by the imagedecoding apparatus according to Embodiment 5;

FIG. 16 shows an overall configuration of a content providing system forimplementing content distribution services;

FIG. 17 shows an overall configuration of a digital broadcasting system;

FIG. 18 shows a block diagram illustrating an example of a configurationof a television;

FIG. 19 shows a block diagram illustrating an example of a configurationof an information reproducing/recording unit that reads and writesinformation from and on a recording medium that is an optical disk;

FIG. 20 shows an example of a configuration of a recording medium thatis an optical disk;

FIG. 21A shows an example of a cellular phone;

FIG. 21B is a block diagram showing an example of a configuration of acellular phone;

FIG. 22 illustrates a structure of multiplexed data;

FIG. 23 schematically shows how each stream is multiplexed inmultiplexed data;

FIG. 24 shows how a video stream is stored in a stream of PES packets inmore detail;

FIG. 25 shows a structure of TS packets and source packets in themultiplexed data;

FIG. 26 shows a data structure of a PMT;

FIG. 27 shows an internal structure of multiplexed data information;

FIG. 28 shows an internal structure of stream attribute information;

FIG. 29 shows steps for identifying video data;

FIG. 30 shows an example of a configuration of an integrated circuit forimplementing the moving picture coding method and the moving picturedecoding method according to each of Embodiments;

FIG. 31 shows a configuration for switching between driving frequencies;

FIG. 32 shows steps for identifying video data and switching betweendriving frequencies;

FIG. 33 shows an example of a look-up table in which video datastandards are associated with driving frequencies;

FIG. 34A is a diagram showing an example of a configuration for sharinga module of a signal processing unit; and

FIG. 34B is a diagram showing another example of a configuration forsharing a module of the signal processing unit.

DETAILED DESCRIPTION

The following describes embodiments according to the present disclosurein detail with reference to the drawings. It should be noted that allthe embodiments described below are specific examples of the presentdisclosure. Numerical values, shapes, materials, constituent elements,arrangement positions and the connection configuration of theconstituent elements, steps, the order of the steps, and the likedescribed in the following embodiments are merely examples, and are notintended to limit the present disclosure. The present disclosure ischaracterized by the appended claims. Therefore, among the constituentelements in the following embodiments, constituent elements that are notdescribed in independent claims that show the most generic concept ofthe present disclosure are described as elements constituting moredesirable configurations, although such constituent elements are notnecessarily required to achieve the object of the present disclosure.

INTRODUCTION

High Efficiency Video Coding (HEVC) can support bit-depth increase inimage decoding. This means that even if the source image is an 8-bitbit-depth image source, a HEVC decoder can support the decoding of thecoded image as a 10 bits bit-depth image to improve the codingefficiency. To reduce the memory bandwidth requirement for interprediction, when decoding a 10 bits bit-depth image, a light compressionscheme can be used to compress a block of 10 bits bit-depth imagesamples for faster memory access.

Currently, there are ways to signal the bit-depths of a reconstructedimage to the decoder through the coded image bit stream. In H.264, thesyntax elements (bit_depth_luma_minus8 and bit_depth_chroma_minus8) inthe sequence parameter set specify the bit-depths of reconstructed lumaand chroma data respectively for a plurality of profiles such as Highprofile, High 10 profile and High 4:2:2 profile. For yet other pluralityof profiles in H.264, the syntax elements (bit_depth_luma_minus8 andbit_depth_chroma_minus8) are not present in the coded image bit stream,and the bit-depths of reconstructed image data is inferred to be equalto 8.

However, one problem is that the signaled bit-depth can be greater thanthe original image bit-depth before coding process, by increase of thebit-depth. For an IPCM block, coding the raw luma and chroma samples ata bit-depth larger than the original image samples is inefficient andreduces coding efficiency.

If the bit-depth of the reconstructed images is greater than thebit-depth of the original images, a light compression scheme may be usedto reduce memory bandwidth. However, an IPCM block containing theoriginal image samples cannot be stored directly into the memory at alower bit-depth as there is a problem differentiating an IPCMreconstructed block and a lightly compressed block in memory. Thistypically results in error in the inter prediction if a wrongdecompression scheme is used for the IPCM constructed image block.

FIG. 1 is a syntax diagram which shows the location of a field parameterin a coded stream. As shown in FIG. 1, if a field 1 of a parameterindicating “reconstructed samples bit-depth” is present, it is stored ina header of sequence of a bitstream. A bitstream comprises a series ofpictures, such as a picture P1 . . . , a picture Pi . . . , wherein eachpicture comprises a series of slices. Here, the picture P1 comprises aslice S1 and a slice S2, wherein a macroblock MBi of the slice S1 is anIPCM block.

In FIG. 1, header information is stored in the header of sequence of thebitstream, wherein the header information comprises the field F1 of aparameter indicating reconstructed samples bit-depth. In the scenario ofFIG. 1, whether or not the macroblock MBi is an IPCM block, the field F1of the fixed length parameter indicating a bit-depth is used forreconstruction purpose (in decoder or encoder).

FIG. 2 is a flowchart which shows a sequence of operations of an imagedecoding method H.264, Section 7.3.5.

A control unit determines whether or not a macroblock type (mb_type) isI_PCM (IPCM block) (Step S202). Here, in the case where the control unitdetermines that the macroblock type is not I_PCM (No in Step S202), themacroblock is processed using other methods for other mb_type values(Step S206).

On the other hand, in the case where the control unit determines themb_type is I_PCM (Yes in Step S202), a byte alignment operation(byte_alignment) is executed on the IPCM macroblock (Step S204). Next,the luma sample values (sample_luma) (for example, 8 bits) of totalnumber of samples [0 . . . Num_of_samples] are read (Step S208). In H.264, ONLY one parsing method is available for I_PCM block of size 16×16(macroblock size).

Thus, there exists a need for a method and apparatus for coding anddecoding images using appropriate bit-depth information. The embodimentsdescribed below offer techniques by which coding efficiency can beimproved by using an adaptive bit-depth.

It should be noted that an IPCM block is a block including IPCM samples.It should also be noted that a IPCM block is treated as one kind of aprediction unit in HEVC. Therefore, an IPCM block is sometimes called anIPCM prediction unit block or an IPCM PU block.

Embodiment 1

FIG. 3 is a block diagram which shows a structure of an image codingapparatus according to Embodiment 1 of the present disclosure. The imagecoding apparatus 300 shown in FIG. 3 is an apparatus for coding an inputimage bit stream on a block-by-block basis so as to generate a codedoutput bitstream.

As shown in FIG. 3, the image coding apparatus 300 includes twoN-bit-depth conversion units 302A and 302B, a subtractor 304A and anadder 304B, a transformation unit 306, a quantization unit 308, aninverse quantization unit 310, an inverse transformation unit 312, aninter/intra prediction unit 314, two multiplexers (MUX units) 316A and316B, a memory 318, a filter unit 319, an entropy coding unit 320, acontrol unit 322, and an optional processing unit 324.

Input images are inputted to the N-bit-depth conversion unit 302A andthe optional processing unit 324. After the input image bit stream isinputted to the N-bit-depth conversion unit 302A, the N-bit-depthconversion unit 302A invokes an N-bit-depth conversion on the inputimages in accordance with a notification determined by the control unit322, and outputs the resulting N-bit-depth converted values to thesubtractor 304A.

A subtractor 304A subtracts, from the N-bit-depth values outputted fromthe N-bit-depth conversion unit 302A, the predicted image valuesoutputted from the inter/intra prediction unit 314, and outputs theresulting values to the transformation unit 306. The transformation unit306 transforms the resulting values into frequency coefficients, andoutputs the resulting frequency coefficients to the quantization unit308. The quantization unit 308 quantizes the inputted frequencycoefficients, and outputs the resulting quantized values to the inversequantization unit 310 and the entropy coding unit 320.

The entropy coding unit 320 encodes the quantized values outputted fromthe quantization unit 308 in accordance with the notification determinedby the control unit 322, and outputs the resulting values to themultiplexer 316B. Here, the entropy coding unit 320 may perform variablelength coding on parameters and the like.

The inverse quantization unit 310 inversely quantizes the quantizedvalued outputted from the quantization unit 308, and outputs theresulting inversely-quantized values to the inverse transformation unit312. The inverse transformation unit 312 performs inverse frequencytransform on the frequency coefficients so as to transform the frequencycoefficients into sample values of the bit stream, and outputs theresulting sample values to the adder 304B. The adder 304B adds thesample values outputted from the inverse transformation unit 312 to thepredicted image values outputted from the inter/intra prediction unit314, and outputs the resulting added values to the multiplexer 316Athrough the filter unit 319.

The filter unit 319 performs filtering, such as deblocking filtering forremoving block distortion, on the resulting added values, as necessary.

The multiplexer 316A selects values from either the values outputtedfrom the filter unit 319 or the values outputted from the N-bit-depthconversion unit 302B in accordance with the notification determined bythe control unit 322, and outputs the resulting values to the memory 318for further prediction. The inter/intra prediction unit 314 searcheswithin reconstructed images stored in the memory 318, and estimates animage area which is e.g. most similar to the input image for prediction.

Furthermore, the input images are inputted to the optional processingunit 324. The optional processing unit 324 manipulates image bit streamssuch as sharpening, smoothing as well as deblocking bit streams, selectsraw fixed-length image samples (in a bit-depth of IPCM samples), andoutputs the resulting selected value to the N-bit-depth conversion unit302B. The N-bit-depth conversion unit 302B invokes an N-bit-depthconversion on the raw image samples and outputs the resulting values tothe multiplexer 316A in accordance with the notification determined bythe control unit 322. The optional processing unit 324 also outputs theresulting value to the multiplexer 316B.

It should be noted that the optional processing unit 324, as describedabove, selects the raw fixed-length image samples at a bit-depth of IPCMsamples. More specifically, the optional processing unit 324 adjusts thebit-depth of the input images to the bit-depth for IPCM. For example,the optional processing unit 324 decreases the bit-depth of the inputimages to the bit-depth for IPCM.

The multiplexer 316B can select values from the values outputted fromthe entropy coding unit 320, or the values outputted from the optionalprocessing unit 324, and output resulting values in accordance with thenotification determined by the control unit 322. The output bitstream ofthe multiplexer 316B is the coded bitstream and is shown later in thesyntax diagram in FIG. 6.

The control unit 322 determines a notification for notifying theN-bit-depth conversion units 302A and 302B whether or not to invokeN-bit-depth conversion on the input images. The control unit 322 alsodetermines a notification for notifying the multiplexer 316A to selectvalues either outputted from the filter unit 319 or outputted from theN-bit-depth conversion unit 320B. Likewise, the control unit 322 alsodetermines a notification for notifying the multiplexer 316B to selectvalues either outputted from the optional processing unit 324 oroutputted from the entropy coding unit 320.

For example, the control unit 322 can use a predetermined scheme, i.e.comparing the number of coded bits produced by the entropy coding unit320 with the number of bits of raw fixed-length samples from theoptional processing unit 324. If coded bits are fewer than bits of rawfixed-length samples, the control unit 322 notifies the multiplexer 316Bto select values outputted from the entropy coding unit 320; otherwise,the control unit 322 notifies the multiplexer 316B to select valuesoutputted from the optional processing unit 324.

The control unit 322 further outputs two parameters (1) a bit-depth ofIPCM samples and (2) a bit-depth of reconstructed samples to the entropycoding unit 320 which writes the two parameters into the outputbitstream.

As described above, the N-bit-depth conversion is converting originalM-bit data to N-bit data by e.g. inserting padding into the originalM-bit data and extending M-bit data to N-bit data or compressing theoriginal M-bit data into N-bit data.

If M=N, then each of the N-bit-depth conversion units 302A and 302Bdirectly outputs M-bit data as the N-bit-depth conversion resultingvalues. In case that the bits of the input data M>N, then each of theN-bit-depth conversion units 302A and 302B may compress M-bit data intoN-bit data and outputs compressed N-bit data. Otherwise, if the bits ofthe input data M<N, then each of the N-bit-depth conversion units 302Aand 302B may insert padding, for example, [0, 0 . . . 0] or [1, 0 . . .0] (in total (N−M) bits) in the beginning of the original M-bit data orat the end of the original M-bit data or between the original M-bitdata, and outputs the padded N-bit data. FIG. 4 is a syntax diagramwhich shows of 8-bit-depth conversion according to Embodiment 1.

In FIG. 4 (a), both a bit-depth for luma component of the reconstructedimages (402) and a bit-depth for chroma component of the reconstructedimages (404) are 8 bits. On the other hand, both a bit-depth for lumacomponent of original IPCM blocks (406) and a bit-depth for chromacomponent of original IPCM blocks (408) are 8 bits. Thus, the bit-depthsof the reconstructed images (8 bits) for both luma component and chromacomponent are equal to the bit-depths of original IPCM blocks (8 bits)for both luma component and chroma component. As a result, neitherbit-increase nor bit-decrease is needed for 8-bit-depth conversion.

In FIG. 4 (b), both a bit-depth for luma component of the reconstructedimages (410) and a bit-depth for chroma component of the reconstructedimages (412) are 8 bits. On the other hand, both a bit-depth for lumacomponent of original IPCM blocks (414) and a bit-depth for chromacomponent of original IPCM blocks (416) are 10 bits. Thus, thebit-depths of the reconstructed image (8 bits) for both luma componentand chroma component are smaller than the bit-depths of original IPCMblocks (10 bits) for both luma component and chroma component. The IPCMblocks undergo a decrease in bit-depth to the level equal to thebit-depth of the reconstructed images by means of, for example,compressing 10-bit data into 8-bit data.

In FIG. 4 (c), both a bit-depth for luma component of the reconstructedimages (418) and a bit-depth for chroma component of the reconstructedimages (420) are 10 bits. On the other hand, both a bit-depth for lumacomponent of original IPCM blocks (422) and a bit-depth for chromacomponent of original IPCM blocks (424) are 8 bits. Thus, the bit-depthsof the reconstructed image (10 bits) for both luma component and chromacomponent are greater than the bit-depths of original IPCM blocks (8bits) for both luma component and chroma component. The IPCM blocksundergo an increase in bit-depth to the level equal to the bit-depth ofthe reconstructed images by means of, for example, inserting 2-bitpadding into the IPCM blocks.

Next, a description is given as to the operations of the image codingapparatus 300 as mentioned above.

FIG. 5 is a flowchart which shows a sequence of operations performed bythe image coding apparatus 300 according to Embodiment 1.

At Step S502, a signal (parameter) sigRec indicating a bit-depth ofreconstructed samples and a signal (parameter) SigPcm indicating abit-depth of IPCM samples are written into the header of image (video)stream. At Step S504, IPCM PU block is written using the bit-depthindicated in the signal sigPcm, e.g. 10 bits. Then, the IPCM PU block isreconstructed by converting the bit-depth indicated in the signal sigPcmto the bit-depth indicated in the signal sigRec, e.g. from 10 bits to 8bits (Step S506).

FIG. 6 is a syntax diagram which shows two field parameters in a codedstream according to Embodiment 1.

As shown in FIG. 6, if a filed 1 for a parameter indicating “bit-depthof reconstructed samples” (e.g. denoted as bit_depth_luma_minus8 andbit_depth_chroma_minus8 shown in FIG. 4) and a filed F2 for a parameterindicating “bit-depth of IPCM samples” (e.g. denoted aspcm_bit_depth_luma_minus1 and pcm_bit_depth_chroma_minus1 shown in FIG.4), are present, they are stored in a header of sequence of a series ofpictures. In FIG. 6, a coded bitstream comprises a series of pictures,such as a picture P1 . . . , a picture Pi . . . , wherein each picturecomprises a series of slices. Here, the picture P1 comprises a slice S1and a slice S2, wherein a block Bi of the slice S1 is an IPCM block.

In FIG. 6, header information includes parameters such as a sequenceheader (sequence parameter set), a picture header (picture parameterset), a slice header, SEI (supplemental enhancement information), NAL(network abstraction layer) etc.

The header information is stored in the header of image stream, whereinthe sequence header comprises the field F1 for the parameter indicating8-bit “bit-depth of reconstructed samples” (SigRec) and the field F2 forthe parameter indicating 10-bit “bit-depth of IPCM samples” (SigPcm). InFIG. 6, the block Bi is an IPCM block, so bit-depth parameter in thefield F2 (sigPcm) is used for block Bi reconstruction rather than thebit-depth parameter in the field F1 (sigRec).

The effect of the present embodiment is coding efficiency improvement ofIPCM data in a coded image bitstream. Using the present embodiment, IPCMdata is coded at its uncompressed bit-depths, which may differ from thebit-depths of the reconstructed image samples. When the bit-depth ofuncompressed samples is smaller than that of the reconstructed samples,the present embodiment removes the redundancy in coding the excess bits.On the other hand, when the bit-depth of the uncompressed samples islarger than that of the reconstructed samples, the present embodimentprovides a structure for faithfully keeping the uncompressed bit-depthin IPCM data without losing bit precision.

Embodiment 2

FIG. 7 is a block diagram which shows a structure of an image decodingapparatus according to Embodiment 2 of the present disclosure. The imagedecoding apparatus 700 shown in FIG. 7 is an apparatus for decoding aninput coded bitstream on a block-by-block basis and outputting images.

The image decoding apparatus 700 includes as shown in FIG. 7, ademultiplexer (DEMUX unit) 702A, a multiplexer (MUX unit) 702B, anentropy decoding unit 704, an adder 706, an inverse quantization unit708, an inverse transformation unit 710, a memory 712, an intra/interprediction unit 714, a control unit 716, a IPCM block parsing unit 718,a filter unit 719, and an N-bit-depth conversion unit 720.

An input coded bitstream is inputted to the demultiplexer 702A, and thedemultiplexer 702A outputs the resulting values whether to the entropydecoding unit 704 or the IPCM block parsing unit 718 in accordance witha notification determined by the control unit 716.

After the input coded bitstream is inputted to the entropy decoding unit704, the entropy decoding unit 704 decodes the values outputted fromdemultiplexer 702A, and outputs the decoded values to the inversequantization unit 708 and the control unit 716. Here, the entropydecoding unit 704 may perform variable length decoding on parameters andthe like.

The inverse quantization unit 708 inversely quantizes the input valuesand outputs the resulting inversely-quantized values to the inversetransformation unit 710. The inverse transformation unit 710 performsinverse frequency transform on frequency coefficients to transform thefrequency coefficients into sample values, and outputs the resultingpixel values to the adder 706. The adder 706 adds the sample valuesoutputted from the inverse transformation unit 710 to the predictedimage values outputted from the inter/intra prediction unit 714, andoutputs the resulting values to the multiplexer 702B through the filterunit 719.

The filter unit 719 performs filtering such as deblocking filtering forremoving block distortion, as necessary.

The multiplexer 702B selects values from either the values outputtedfrom the filter unit 719 or the values outputted from N-bit-depthconversion unit 720 in accordance with the notification determined bythe control unit 716, and outputs the resulting values to the memory 712for further prediction. The decoded images are outputted to display fromthe memory 712. In addition, the inter/intra prediction unit 714searches within images stored in the memory 712, and estimates an imagearea which is e.g. most similar to the decoded images for prediction.

Returning to the IPCM block parsing unit 718 and the N-bit-depthconversion unit 720, the parsing and converting processes rely on twoparameters “bit-depth of IPCM samples (sigPcm)” and “bit-depth ofreconstructed samples (sigRec)”. The two parameters “bit-depth of IPCMsamples (sigPcm)” and “bit-depth of reconstructed samples (sigRec)” areobtained from the entropy decoding unit 704 from the header of the inputbitstream.

The input coded bitstream and the signal sigPcm (e.g. indicating 10bits) outputted from the control unit 716 are inputted to the IPCM blockparsing unit 718, and the IPCM block parsing unit 718 outputs theresulting parsed values to the N-bit-depth conversion unit 720. TheN-bit-depth conversion unit 720 invokes an N-bit-depth conversion usingthe signal sigRec obtained from the control unit 716 and using theparsed value outputted from the IPCM block parsing unit 718, and outputsthe resulting converted value to the multiplexer 702B.

The multiplexer 702B can select values from either the value outputtedform the filter unit 719 or the values outputted from the N-bit-depthconversion unit 720 in accordance with the notification determined bythe control unit 716.

The control unit 716 determines a notification for notifying thedemultiplexer 702A to output whether to the entropy decoding unit 704 orto the IPCM block parsing unit 718. The control unit 716 also determinesa notification for notifying the multiplexer 702B to select values fromeither the value outputted from the filter unit 719 or the valuesoutputted from the N-bit-depth conversion unit 720. In addition, thecontrol unit 716 further provides with two signal sigPcm (e.g. 10 bits)and the signal sigRec (N bits) as input values to IPCM block parsingunit 718 and to the N-bit-depth conversion unit 720, respectively.

Next, a description is given as to the operations of the image decodingapparatus 700 as mentioned above.

FIG. 8 is a flowchart which shows a sequence of operations performed bythe image decoding apparatus 700 according to Embodiment 2.

At Step S802, a determination is made whether or not the PU_type(prediction unit type) is I_PCM. When the PU_type is not I_PCM, as aresult of this determination (No in Step S802), the other methods forother PU_type values are used to decode the block (Step S804).

On the other hand, when the PU_type is I_PCM, as a result of thisdetermination (Yes in Step S802), the control unit 716 obtains thesignal sigRec and the signal sigPcm from the header of image stream(Step S806). Next, the I_PCM PU block are read using bit-depth of rawfixed-length samples indicated in the sigPcm, e.g. 10 bits (Step S808).Then, it is determined whether or not the bit-depth indicated in thesignal sigRec and the bit-depth indicated in the signal sigPcm aredifferent (Step S810). When the bit-depth indicated in the signal sigRecis different from the bit-depth indicated in the signal sigPcm (Yes inStep S810), an N-bit-depth conversion is invoked using the signalsigRec, e.g. from 10 bits to 8 bits (Step S812).

As described above, a parameter “bit-depth of IPCM samples” in a headerof an image sequence can be used to identify the bit-depth of IPCMblocks so that a decoder knows how many bits per sample is required forthe parsing of an IPCM block.

In the case that the bit-depth of the reconstructed images is greater(smaller) than the bit-depth of IPCM blocks and a light memorycompression is used to compress the reconstructed images, the IPCMblocks would undergo an increase (decrease) in bit-depth to the levelequal to the bit-depth of the reconstructed image and the same lightcompression scheme would be applied to the IPCM block as well tomaintain consistency in the decompression process for inter prediction.When a light memory compression is used, IPCM samples are treatedequally as non-IPCM samples due to the bit-depth conversion process.

The effect of the present embodiment is to enable the decoding of acoded video data which is coded in the form of coding efficiencyimprovement of IPCM data. When the bit-depth of uncompressed samples issmaller than that of the reconstructed samples, the present embodimentremoves the redundancy in coding the excess bits. On the other hand,when the bit-depth of the uncompressed samples is larger than that ofthe reconstructed samples, the present embodiment provides a means forfaithfully keeping the uncompressed bit-depth in IPCM data withoutlosing bit precision.

Even if bit-depths of IPCM data and non-IPCM data are different,decoding can be appropriately by using the parameter in the coded videodata which indicates a bit-depth of IPCM data.

Embodiment 3

In Embodiment 3, a description is given for characteristic operationsperformed by the image coding apparatus 300 described in Embodiment 1.

FIG. 9 is a flowchart which shows a coding method of coding an imagebitstream according to Embodiment 3 of the present disclosure. At stepS902, a first parameter representing a bit-depth of raw fixed-lengthsamples signaled within the image bit stream is written into a header ofthe image (video) bit stream. At step S904, a second parameterrepresenting a bit-depth of reconstructed samples from the image bitstream is written into the header of the image bit stream. At step S906,a subgroup of raw fixed-length samples is written at bits per sampleinto the image bit stream based on the first parameter. At Step S908,the subgroup of raw fixed-length samples is reconstructed, wherein thereconstructing includes converting the bit-depth of the subgroup of rawfixed-length samples from the first parameter to the second parameter.

Embodiment 4

The image coding apparatus according to Embodiment 4 includes thecharacteristic constituent elements in the image coding apparatus 300described in Embodiment 1. Furthermore, the image decoding apparatusaccording to Embodiment 4 includes the characteristic constituentelements in the image decoding apparatus 700 described in Embodiment 2.

FIG. 10A is a block diagram which shows a structure of the image codingapparatus according to Embodiment 4 of the present disclosure. The imagecoding apparatus 1000 shown in FIG. 10A codes images to generate a codedstream. Then, the image coding apparatus 1000 includes a first writingunit 1001 and a second writing unit 1002. The first writing unit 1001and the second writing unit 1002 mainly corresponds to the entropycoding unit 320 according to Embodiment 1.

FIG. 10B is a flowchart which shows operations performed by the imagecoding apparatus 1000 shown in FIG. 10A.

As shown in FIG. 10B, the first writing unit 1001 writes the firstparameter representing the first bit-depth that is a bit-depth ofreconstructed samples of image, into a sequence parameter set in a codedstream to be generated (S1001). The second writing unit 1002 writes thesecond parameter, which represents the second bit-depth that is abit-depth of IPCM samples in image and is different from the firstparameter, into the sequence parameter set (S1002).

Thereby, it is possible to set a bit-depth of IPCM samples separatelyand independently from a bit-depth of reconstructed samples. Therefore,redundant data of IPCM samples can be reduced. As a result, codingefficiency can be improved.

FIG. 11A is a block diagram which shows a structure of the imagedecoding apparatus according to Embodiment 4. The image decodingapparatus 1100 shown in FIG. 11A decodes the images included in thecoded stream. Then, the image decoding apparatus 1100 includes a firstobtaining unit 1101 and a second obtaining unit 1102. The firstobtaining unit 1101 and the second obtaining unit 1102 mainly correspondto the entropy decoding unit 704 according to Embodiment 2.

FIG. 11B is a flowchart which shows operations performed by the imagedecoding apparatus 1100 shown in FIG. 11A.

As shown in FIG. 11B, the first obtaining unit 1101 obtains the firstparameter representing the first bit-depth that is a bit-depth ofreconstructed samples of image, from the sequence parameter set in thecoded stream (S1101). The second obtaining unit 1102 obtains the secondparameter, which represents the second bit-depth that is a bit-depth ofIPCM samples in image and is different from the first parameter, fromthe sequence parameter set (S1002).

Therefore, it is possible to obtain the bit-depth of IPCM samplesseparately and independently from the bit-depth of reconstructedsamples. Therefore, redundant data of IPCM samples can be reduced. As aresult, coding efficiency can be improved.

Embodiment 5

The image coding apparatus according to Embodiment 5 of the presentdisclosure includes characteristic constituent elements in the imagecoding apparatus 300 described in Embodiment 1. Furthermore, the imagedecoding apparatus according to Embodiment 5 includes the characteristicconstituent elements in the image decoding apparatus 700 described inEmbodiment 2. It should be noted that, in Embodiment 5,arbitrarily-addable constituent elements are described in addition tothe constituent elements described in Embodiment 4.

FIG. 12 is a block diagram which shows a structure of the image codingapparatus according to the present embodiment. The image codingapparatus 1200 shown in FIG. 12 includes a first writing unit 1201, asecond writing unit 1202, a third writing unit 1203, a fourth writingunit 1204, a reconstruction unit 1205, a conversion unit 1206, abit-depth decrease unit 1207, and a bit-depth increase unit 1208.

The first writing unit 1201 and the second writing unit 1202 are thesame constituent elements as the first writing unit 1001 and the secondwriting unit 1002 in the image coding apparatus 1000, respectively. Theother constituent elements are additional constituent elements, a partor all of which is arbitrarily added.

The third writing unit 1203 mainly corresponds to the multiplexer 316Baccording to Embodiment 1. The fourth writing unit 1204 mainlycorresponds to the entropy coding unit 320 according to Embodiment 1.The conversion unit 1206 mainly corresponds to the N-bit-depthconversion unit 302 B according to Embodiment 1. The bit-depth decreaseunit 1207 mainly corresponds to the optional processing unit 324according to Embodiment 1. The bit-depth increase unit 1208 mainlycorresponds to the N-bit-depth conversion unit 302A according toEmbodiment 1.

The reconstruction unit 1205 mainly corresponds to the adder 304Baccording to Embodiment 1. The reconstruction unit 1205 may include theinverse quantization unit 310, the inverse transformation unit 312, thefilter unit 319, and the inter/intra prediction unit 314 according toEmbodiment 1.

FIG. 13B is a flowchart which shows operations performed by the imagecoding apparatus 1200 shown in FIG. 12. As shown in FIG. 13, the firstwriting unit 1201 writes the first parameter representing the firstbit-depth that is a bit-depth of reconstructed samples of image, to asequence parameter set in a coded stream to be generated (S1301).

The second writing unit 1201 writes the second parameter, whichrepresents the second bit-depth that is a bit-depth of IPCM samples inimage and is different from the first parameter, into the sequenceparameter set (S1302). Here, typically, the second writing unit 1202writes the second parameter representing the second bit-depth that isequal to or smaller than the first bit-depth.

The first writing unit 1201 may write the first parameter representingthe first bit-depth that is larger than the third bit-depth that is abit-depth of original samples of image. In this case, the bit-depthincrease unit 1208 converts the original samples at the third bit-depthinto samples at the first bit-depth, so as to increase the bit-depth ofreconstructed samples corresponding to the original samples (S1303).

The second writing unit 1202 may write the second parameter representingthe second bit-depth that is smaller than the third bit-depth that is abit-depth of original samples of image. In this case, the bit-depthdecrease unit 1207 converts the original samples at the third bit-depthinto samples at the second bit-depth, so as to decrease the bit-depth ofIPCM samples corresponding to the original samples (S1304).

The reconstruction unit 1205 reconstructs samples at the first bit-depthfrom the coded samples of image, so as to generate reconstructed samples(S1305). Here, the coded samples are generated by performing at least apart of coding processing for the original samples of image. Theconversion unit 1206 converts the IPCM samples at the second bit-depthinto reconstructed samples at the first bit-depth (S1306).

The third writing unit 1203 writes the IPCM samples at the secondbit-depth into the coded stream (S1307). The fourth writing unit 1204writes coded samples, which are coded using the reconstructed samples atthe first bit-depth, into the coded stream (S1308).

Therefore, the image coding apparatus 1200 can appropriately performimage processing by using the bit-depth of reconstructed samples and thebit-depth of IPCM samples. For example, a large bit-depth is used forreconstructed samples, and a small bit-depth is used for IPCM samples.Therefore, both image quality improvement and coding efficiencyimprovement can be achieved.

It should be noted that an order of steps is not limited to the ordershown in FIG. 13, but may be changed. It should also be noted that it ispossible to eliminate a part or all of steps, in particular, stepssurrounded by a broken line. It should also be noted that the imagecoding apparatus 1200 may further include a coding processing unit thatcodes original samples using reconstructed samples. The codingprocessing unit mainly corresponds to the inter/intra prediction unit314, the subtractor 304A, the entropy coding unit 320, the quantizationunit 308, the conversion unit 306, and the like according to Embodiment1.

FIG. 14A is a block diagram which shows a structure of the imagedecoding apparatus according to the present embodiment. The imagedecoding apparatus 1400 shown in FIG. 14 includes a first obtaining unit1401, a second obtaining unit 1402, a third obtaining unit 1403, afourth obtaining unit 1404, a reconstruction unit 1405, a conversionunit 1406, and a bit-depth increase unit 1407.

The first obtaining unit 1401 and the second obtaining unit 1402 are thesame constituent elements as the first obtaining unit 1101 and thesecond obtaining unit 1102 in the image decoding apparatus 1100,respectively. The other constituent elements are additional constituentelements, a part or all of which is arbitrarily added.

The third obtaining unit 1403 mainly corresponds to the IPCM blockparsing unit 718 according to Embodiment 2. The fourth obtaining unit1404 mainly corresponds to the entropy decoding unit 704 according toEmbodiment 2. The conversion unit 1406 mainly corresponds to theN-bit-depth conversion unit 720 according to Embodiment 2. The bit-depthincrease unit 1407 mainly corresponds to the N-bit-depth conversion unit720 according to Embodiment 2.

The reconstruction unit 1405 mainly corresponds to the adder 706according to Embodiment 2. The reconstruction unit 1405 may include theinverse quantization unit 708, the inverse transformation unit 710, thefilter unit 719, and the inter/intra prediction unit 714 according toEmbodiment 2.

FIG. 15 is a flowchart which shows operations performed by the imagedecoding apparatus 1400 shown in FIG. 14. As shown in FIG. 15, the firstobtaining unit 1401 obtains the first parameter representing the firstbit-depth that is a bit-depth of reconstructed samples of image, fromthe sequence parameter set in the coded stream (S1501).

The second obtaining unit 1402 obtains the second parameter, whichrepresents the second bit-depth that is a bit-depth of IPCM samples inimage and is different from the first parameter, from the sequenceparameter set (S1502). Here, typically, the second obtaining unit 1402obtains the second parameter representing the second bit-depth that isequal to or smaller than the first bit-depth.

The second obtaining unit 1402 may obtain the second parameterrepresenting the second bit-depth that is smaller than the firstbit-depth. For example, the second obtaining unit 1402 obtains thesecond parameter representing the second bit-depth that is smaller thanthe third bit-depth that is a bit-depth of original samples of image.For example, the first obtaining unit 1401 obtains the first parameterrepresenting the first bit-depth that is larger than the third bit-depththat is a bit-depth of original samples of image.

The fourth obtaining unit 1404 obtains coded samples to be decoded usingthe reconstructed samples at the first bit-depth, from the coded stream(S1503). The third obtaining unit 1403 obtains the IPCM samples at thesecond bit-depth from the coded stream (S1504). The reconstruction unit1405 reconstructs samples at the first bit-depth from the coded samplesof image, so as to generate reconstructed samples (S1505).

When the second obtaining unit 1402 obtains the second parameterrepresenting the second bit-depth that is smaller than the firstbit-depth, the bit-depth increase unit 1407 converts IPCM samples at thesecond bit-depth into samples at the first bit-depth, so as to increasethe bit-depth of IPCM samples (S1506) The transformation unit 1406converts the IPCM samples at the second bit-depth into reconstructedsamples at the first bit-depth (S1507).

Therefore, the image decoding apparatus 1400 can appropriately performimage processing by using the bit-depth of reconstructed samples and thebit-depth of IPCM samples. For example, a large bit-depth is used forreconstructed samples, and a small bit-depth is used for IPCM samples.Therefore, both image quality improvement and coding efficiencyimprovement can be achieved.

It should be noted that an order of steps is not limited to the ordershown in FIG. 15, but may be changed. It should also be noted that it ispossible to eliminate a part or all of steps, in particular, stepssurrounded by a broken line. It should also be noted that the imagedecoding apparatus 1400 may further include a decoding processing unitthat decodes coded samples by using reconstructed samples. The decodingprocessing unit mainly corresponds to the inter/intra prediction unit714, the adder 706, the entropy decoding unit 704, the inversequantization unit 708, the inverse transformation unit 710, and the likeaccording to Embodiment 2.

Although the image coding apparatus and the image decoding apparatusaccording to the present disclosure have been described with referenceto a plurality of embodiments as above, the present disclosure is notlimited to these embodiments. Those skilled in the art will be readilyappreciated that various modifications and combinations of theconstituent elements are possible in the exemplary embodiments. Suchmodifications and combinations are also embodiments of the presentdisclosure.

For example, a step to be performed by a specific processing unit may beperformed by a different processing unit. It should be noted that anorder of executing steps may be changed, or a plurality of steps may beexecuted in parallel.

It should also be noted that the image coding apparatus and the imagedecoding apparatus according to the embodiments of the presentdisclosure may be implemented as an image coding/decoding apparatus thatis a combination of arbitral constituent elements included in the magecoding apparatus and the image decoding apparatus. For example, theimage coding/decoding apparatus according to an embodiment of thepresent disclosure includes: an image coding unit that is the imagecoding apparatus according to one of the embodiments of the presentdisclosure; and an image decoding unit that is the image decodingapparatus according to one of the embodiments of the present disclosure.

It should also be noted that the present disclosure may be implementednot only as the image coding apparatus and the image decoding apparatus,but also as methods including steps performed by the processing units inthe image coding apparatus and the image decoding apparatus. Forexample, these steps are executed by a computer. Furthermore, thepresent disclosure may be implemented as a program causing a computer toexecute the steps included in the methods. Moreover, the presentdisclosure may be implemented as a non-transitory computer-readablerecording medium, such as a CD-ROM, on which the program is recorded.

The constituent elements included in the image coding apparatus and theimage decoding apparatus may be implemented into a Large ScaleIntegration (LSI) which is an integrated circuit. These constituentelements may be integrated separately, or a part or all of them may beintegrated into a single chip. Here, the integrated circuit is referredto as a LSI, but the integrated circuit can be called an IC, a systemLSI, a super LSI or an ultra LSI depending on their degrees ofintegration.

It should be noted that the technique of integrated circuit is notlimited to the LSI, and it may be implemented as a dedicated circuit ora general-purpose processor. It is also possible to use a FieldProgrammable Gate Array (FPGA) that can be programmed aftermanufacturing the LSI, or a reconfigurable processor in which connectionand setting of circuit cells inside the LSI can be reconfigured.

Furthermore, if due to the progress of semiconductor technologies ortheir derivations, new technologies for integrated circuits appear to bereplaced with the LSIs, it is, of course, possible to use suchtechnologies to implement the constituent elements included in the imagecoding apparatus and the image decoding apparatus as an integratedcircuit.

Embodiment 6

The processing described in each of Embodiments can be simplyimplemented in an independent computer system, by recording, in arecording medium, a program for implementing the configurations of themoving picture coding method (image coding method) and the movingpicture decoding method (image decoding method) described in each ofEmbodiments. The recording media may be any recording media as long asthe program can be recorded, such as a magnetic disk, an optical disk, amagnetic optical disk, an IC card, and a semiconductor memory.

Hereinafter, the applications to the moving picture coding method (imagecoding method) and the moving picture decoding method (image decodingmethod) described in each of Embodiments and systems using thereof willbe described. The system has a feature of having an image coding anddecoding apparatus that includes an image encoding apparatus using theimage encoding method and an image decoding apparatus using the imagedecoding method. Other configurations in the system can be changed asappropriate depending on the cases.

FIG. 16 illustrates an overall configuration of a content providingsystem ex100 for implementing content distribution services. The areafor providing communication services is divided into cells of desiredsize, and base stations ex106, ex107, ex108, ex109, and ex110 which arefixed wireless stations are placed in each of the cells.

The content providing system ex100 is connected to devices, such as acomputer ex111, a personal digital assistant (PDA) ex112, a cameraex113, a cellular phone ex114 and a game machine ex115, via the Internetex101, an Internet service provider ex102, a telephone network ex104, aswell as the base stations ex106 to ex110, respectively.

However, the configuration of the content providing system ex100 is notlimited to the configuration shown in FIG. 16, and a combination inwhich any of the elements are connected is acceptable. In addition, eachdevice may be directly connected to the telephone network ex104, ratherthan via the base stations ex106 to ex110 which are the fixed wirelessstations. Furthermore, the devices may be interconnected to each othervia a short distance wireless communication and others.

The camera ex113, such as a digital video camera, is capable ofcapturing video. A camera ex116, such as a digital video camera, iscapable of capturing both still images and video. Furthermore, thecellular phone ex114 may be the one that meets any of the standards suchas Global System for Mobile Communications (GSM), Code Division MultipleAccess (CDMA), Wideband-Code Division Multiple Access (W-CDMA), LongTerm Evolution (LTE), and High Speed Packet Access (HSPA).Alternatively, the cellular phone ex114 may be a Personal HandyphoneSystem (PHS).

In the content providing system ex100, a streaming server ex103 isconnected to the camera ex113 and others via the telephone network ex104and the base station ex109, which enables distribution of images of alive show and others. In such a distribution, a content (for example,video of a music live show) captured by the user using the camera ex113is coded as described above in each of Embodiments (i.e., the camerafunctions as the image coding apparatus of the present invention), andthe coded content is transmitted to the streaming server ex103. On theother hand, the streaming server ex103 carries out stream distributionof the transmitted content data to the clients upon their requests. Theclients include the computer ex111, the PDA ex112, the camera ex113, thecellular phone ex114, and the game machine ex115 that are capable ofdecoding the above-mentioned coded data. Each of the devices that havereceived the distributed data decodes and reproduces the coded data(i.e., the devices each function as the image decoding apparatus of thepresent invention).

The captured data may be coded by the camera ex113 or the streamingserver ex103 that transmits the data, or the coding processes may beshared between the camera ex113 and the streaming server ex103.Similarly, the distributed data may be decoded by the clients or thestreaming server ex103, or the decoding processes may be shared betweenthe clients and the streaming server ex103. Furthermore, the data of thestill images and video captured by not only the camera ex113 but alsothe camera ex116 may be transmitted to the streaming server ex103through the computer ex111. The coding processes may be performed by thecamera ex116, the computer ex111, or the streaming server ex103, orshared among them.

Furthermore, the coding and decoding processes may be performed by anLSI ex500 generally included in each of the computer ex111 and thedevices. The LSI ex500 may be configured of a single chip or a pluralityof chips. Software for coding and decoding video may be integrated intosome type of a recording medium (such as a CD-ROM, a flexible disk, anda hard disk) that is readable by the computer ex111 and others, and thecoding and decoding processes may be performed using the software.Furthermore, when the cellular phone ex114 is equipped with a camera,the image data obtained by the camera may be transmitted. The video datais data coded by the LSI ex500 included in the cellular phone ex114.

Furthermore, the streaming server ex103 may be composed of servers andcomputers, and may decentralize data and process the decentralized data,record, or distribute data.

As described above, the clients may receive and reproduce the coded datain the content providing system ex100. In other words, the clients canreceive and decode information transmitted by the user, and reproducethe decoded data in real time in the content providing system ex100, sothat the user who does not have any particular right and equipment canimplement personal broadcasting.

Aside from the example of the content providing system ex100, at leastone of the moving picture coding apparatus (image coding apparatus) andthe moving picture decoding apparatus (image decoding apparatus)described in each of Embodiments may be implemented in a digitalbroadcasting system ex200 illustrated in FIG. 17. More specifically, abroadcast station ex201 communicates or transmits, via radio waves to abroadcast satellite ex202, multiplexed data obtained by multiplexingaudio data and others onto video data. The video data is data coded bythe moving picture coding method described in each of Embodiments (i.e.,data coded by the image coding apparatus of the present invention). Uponreceipt of the multiplexed data, the broadcast satellite ex202 transmitsradio waves for broadcasting. Then, a home-use antenna ex204 with asatellite broadcast reception function receives the radio waves. Next, adevice such as a television (receiver) ex300 and a set top box (STB)ex217 decodes the received multiplexed data, and reproduces the decodeddata (i.e., the device functions as the image coding apparatus of thepresent invention).

Furthermore, a reader/recorder ex218 (i) reads and decodes themultiplexed data recorded on a recording media ex215, such as a DVD anda BD, or (i) codes video signals in the recording medium ex215, and insome cases, writes data obtained by multiplexing an audio signal on thecoded data. The reader/recorder ex218 can include the moving picturedecoding apparatus or the moving picture coding apparatus as shown ineach of Embodiments. In this case, the reproduced video signals aredisplayed on the monitor ex219, and can be reproduced by another deviceor system using the recording medium ex215 on which the multiplexed datais recorded. It is also possible to implement the moving picturedecoding apparatus in the set top box ex217 connected to the cable ex203for a cable television or to the antenna ex204 for satellite and/orterrestrial broadcasting, so as to display the video signals on themonitor ex219 of the television ex300. The moving picture decodingapparatus may be implemented not in the set top box but in thetelevision ex300.

FIG. 18 illustrates the television (receiver) ex300 that uses the movingpicture coding method and the moving picture decoding method describedin each of Embodiments. The television ex300 includes: a tuner ex301that obtains or provides multiplexed data obtained by multiplexing audiodata onto video data, through the antenna ex204 or the cable ex203, etc.that receives a broadcast; a modulation/demodulation unit ex302 thatdemodulates the received multiplexed data or modulates data intomultiplexed data to be supplied outside; and amultiplexing/demultiplexing unit ex303 that demultiplexes the modulatedmultiplexed data into video data and audio data, or multiplexes videodata and audio data coded by a signal processing unit ex306 into data.

The television ex300 further includes: a signal processing unit ex306including an audio signal processing unit ex304 and a video signalprocessing unit ex305 that decode audio data and video data and codeaudio data and video data, (which function as the image coding apparatusand the image decoding apparatus), respectively; and an output unitex309 including a speaker ex307 that provides the decoded audio signal,and a display unit ex308 that displays the decoded video signal, such asa display. Furthermore, the television ex300 includes an interface unitex317 including an operation input unit ex312 that receives an input ofa user operation. Furthermore, the television ex300 includes a controlunit ex310 that controls overall each constituent element of thetelevision ex300, and a power supply circuit unit ex311 that suppliespower to each of the elements. Other than the operation input unitex312, the interface unit ex317 may include: a bridge ex313 that isconnected to an external device, such as the reader/recorder ex218; aslot unit ex314 for enabling attachment of the recording medium ex216,such as an SD card; a driver ex315 to be connected to an externalrecording medium, such as a hard disk; and a modem ex316 to be connectedto a telephone network. Here, the recording medium ex216 canelectrically record information using a non-volatile/volatilesemiconductor memory element for storage. The constituent elements ofthe television ex300 are connected to each other through a synchronousbus.

First, the configuration in which the television ex300 decodesmultiplexed data obtained from outside through the antenna ex204 andothers and reproduces the decoded data will be described. In thetelevision ex300, upon a user operation through a remote controllerex220 and others, the multiplexing/demultiplexing unit ex303demultiplexes the multiplexed data demodulated by themodulation/demodulation unit ex302, under control of the control unitex310 including a CPU. Furthermore, the audio signal processing unitex304 decodes the demultiplexed audio data, and the video signalprocessing unit ex305 decodes the demultiplexed video data, using thedecoding method described in each of Embodiments, in the televisionex300. The output unit ex309 provides the decoded video signal and audiosignal outside, respectively. When the output unit ex309 provides thevideo signal and the audio signal, the signals may be temporarily storedin buffers ex318 and ex319, and others so that the signals arereproduced in synchronization with each other. Furthermore, thetelevision ex300 may read multiplexed data not through a broadcast andothers but from the recording media ex215 and ex216, such as a magneticdisk, an optical disk, and a SD card. Next, a configuration in which thetelevision ex300 codes an audio signal and a video signal, and transmitsthe data outside or writes the data on a recording medium will bedescribed. In the television ex300, upon a user operation through theremote controller ex220 and others, the audio signal processing unitex304 codes an audio signal, and the video signal processing unit ex305codes a video signal, under control of the control unit ex310 using thecoding method described in each of Embodiments. Themultiplexing/demultiplexing unit ex303 multiplexes the coded videosignal and audio signal, and provides the resulting signal outside. Whenthe multiplexing/demultiplexing unit ex303 multiplexes the video signaland the audio signal, the signals may be temporarily stored in thebuffers ex320 and ex321, and others so that the signals are reproducedin synchronization with each other. Here, the buffers ex318, ex319,ex320, and ex321 may be plural as illustrated, or at least one buffermay be shared in the television ex300. Furthermore, data may be storedin a buffer so that the system overflow and underflow may be avoidedbetween the modulation/demodulation unit ex302 and themultiplexing/demultiplexing unit ex303, for example.

Furthermore, the television ex300 may include a configuration forreceiving an AV input from a microphone or a camera other than theconfiguration for obtaining audio and video data from a broadcast or arecording medium, and may code the obtained data. Although thetelevision ex300 can code, multiplex, and provide outside data in thedescription, it may be capable of only receiving, decoding, andproviding outside data but not the coding, multiplexing, and providingoutside data.

Furthermore, when the reader/recorder ex218 reads or writes multiplexeddata from or on a recording medium, one of the television ex300 and thereader/recorder ex218 may decode or code the multiplexed data, and thetelevision ex300 and the reader/recorder ex218 may share the decoding orcoding.

As an example, FIG. 19 illustrates a configuration of an informationreproducing/recording unit ex400 when data is read or written from or onan optical disk. The information reproducing/recording unit ex400includes constituent elements ex401, ex402, ex403, ex404, ex405, ex406,and ex407 to be described hereinafter. The optical head ex401 irradiatesa laser spot in a recording surface of the recording medium ex215 thatis an optical disk to write information, and detects reflected lightfrom the recording surface of the recording medium ex215 to read theinformation. The modulation recording unit ex402 electrically drives asemiconductor laser included in the optical head ex401, and modulatesthe laser light according to recorded data. The reproductiondemodulating unit ex403 amplifies a reproduction signal obtained byelectrically detecting the reflected light from the recording surfaceusing a photo detector included in the optical head ex401, anddemodulates the reproduction signal by separating a signal componentrecorded on the recording medium ex215 to reproduce the necessaryinformation. The buffer ex404 temporarily holds the information to berecorded on the recording medium ex215 and the information reproducedfrom the recording medium ex215. The disk motor ex405 rotates therecording medium ex215. The servo control unit ex406 moves the opticalhead ex401 to a predetermined information track while controlling therotation drive of the disk motor ex405 so as to follow the laser spot.The system control unit ex407 controls overall the informationreproducing/recording unit ex400. The reading and writing processes canbe implemented by the system control unit ex407 using variousinformation stored in the buffer ex404 and generating and adding newinformation as necessary, and by the modulation recording unit ex402,the reproduction demodulating unit ex403, and the servo control unitex406 that record and reproduce information through the optical headex401 while being operated in a coordinated manner. The system controlunit ex407 includes, for example, a microprocessor, and executesprocessing by causing a computer to execute a program for read andwrite.

Although the optical head ex401 irradiates a laser spot in thedescription, it may perform high-density recording using near fieldlight.

FIG. 20 illustrates the recording medium ex215 that is the optical disk.On the recording surface of the recording medium ex215, guide groovesare spirally formed, and an information track ex230 records, in advance,address information indicating an absolute position on the diskaccording to change in a shape of the guide grooves. The addressinformation includes information for determining positions of recordingblocks ex231 that are a unit for recording data. Reproducing theinformation track ex230 and reading the address information in anapparatus that records and reproduces data can lead to determination ofthe positions of the recording blocks. Furthermore, the recording mediumex215 includes a data recording area ex233, an inner circumference areaex232, and an outer circumference area ex234. The data recording areaex233 is an area for use in recording the user data. The innercircumference area ex232 and the outer circumference area ex234 that areinside and outside of the data recording area ex233, respectively arefor specific use except for recording the user data. The informationreproducing/recording unit 400 reads and writes coded audio, coded videodata, or multiplexed data obtained by multiplexing the coded audio andvideo data, from and on the data recording area ex233 of the recordingmedium ex215.

Although an optical disk having a layer, such as a DVD and a BD isdescribed as an example in the description, the optical disk is notlimited to such, and may be an optical disk having a multilayerstructure and capable of being recorded on a part other than thesurface. Furthermore, the optical disk may have a structure formultidimensional recording/reproduction, such as recording ofinformation using light of colors with different wavelengths in the sameportion of the optical disk and for recording information havingdifferent layers from various angles.

Furthermore, a car ex210 having an antenna ex205 can receive data fromthe satellite ex202 and others, and reproduce video on a display devicesuch as a car navigation system ex211 set in the car ex210, in thedigital broadcasting system ex200. Here, a configuration of the carnavigation system ex211 will be a configuration, for example, includinga GPS receiving unit from the configuration illustrated in FIG. 18. Thesame will be true for the configuration of the computer ex111, thecellular phone ex114, and others.

FIG. 21A illustrates the cellular phone ex114 that uses the movingpicture coding method and the moving picture decoding method describedin Embodiments. The cellular phone ex114 includes: an antenna ex350 fortransmitting and receiving radio waves through the base station ex110; acamera unit ex365 capable of capturing moving and still images; and adisplay unit ex358 such as a liquid crystal display for displaying thedata such as decoded video captured by the camera unit ex365 or receivedby the antenna ex350. The cellular phone ex114 further includes: a mainbody unit including an operation key unit ex366; an audio output unitex357 such as a speaker for output of audio; an audio input unit ex356such as a microphone for input of audio; a memory unit ex367 for storingcaptured video or still pictures, recorded audio, coded or decoded dataof the received video, the still pictures, e-mails, or others; and aslot unit ex364 that is an interface unit for a recording medium thatstores data in the same manner as the memory unit ex367.

Next, an example of a configuration of the cellular phone ex114 will bedescribed with reference to FIG. 21B. In the cellular phone ex114, amain control unit ex360 designed to control overall each unit of themain body including the display unit ex358 as well as the operation keyunit ex366 is connected mutually, via a synchronous bus ex370, to apower supply circuit unit ex361, an operation input control unit ex362,a video signal processing unit ex355, a camera interface unit ex363, aliquid crystal display (LCD) control unit ex359, amodulation/demodulation unit ex352, a multiplexing/demultiplexing unitex353, an audio signal processing unit ex354, the slot unit ex364, andthe memory unit ex367.

When a call-end key or a power key is turned ON by a user's operation,the power supply circuit unit ex361 supplies the respective units withpower from a battery pack so as to activate the cell phone ex114.

In the cellular phone ex114, the audio signal processing unit ex354converts the audio signals collected by the audio input unit ex356 invoice conversation mode into digital audio signals under the control ofthe main control unit ex360 including a CPU, ROM, and RAM. Then, themodulation/demodulation unit ex352 performs spread spectrum processingon the digital audio signals, and the transmitting and receiving unitex351 performs digital-to-analog conversion and frequency conversion onthe data, so as to transmit the resulting data via the antenna ex350.Also, in the cellular phone ex114, the transmitting and receiving unitex351 amplifies the data received by the antenna ex350 in voiceconversation mode and performs frequency conversion and theanalog-to-digital conversion on the data. Then, themodulation/demodulation unit ex352 performs inverse spread spectrumprocessing on the data, and the audio signal processing unit ex354converts it into analog audio signals, so as to output them via theaudio output unit ex357.

Furthermore, when an e-mail in data communication mode is transmitted,text data of the e-mail inputted by operating the operation key unitex366 and others of the main body is sent out to the main control unitex360 via the operation input control unit ex362. The main control unitex360 causes the modulation/demodulation unit ex352 to perform spreadspectrum processing on the text data, and the transmitting and receivingunit ex351 performs the digital-to-analog conversion and the frequencyconversion on the resulting data to transmit the data to the basestation ex110 via the antenna ex350. When an e-mail is received,processing that is approximately inverse to the processing fortransmitting an e-mail is performed on the received data, and theresulting data is provided to the display unit ex358.

When video, still images, or video and audio in data communication modeis or are transmitted, the video signal processing unit ex355 compressesand codes video signals supplied from the camera unit ex365 using themoving picture coding method shown in each of Embodiments (i.e.,functions as the image coding apparatus of the present invention), andtransmits the coded video data to the multiplexing/demultiplexing unitex353. In contrast, during when the camera unit ex365 captures video,still images, and others, the audio signal processing unit ex354 codesaudio signals collected by the audio input unit ex356, and transmits thecoded audio data to the multiplexing/demultiplexing unit ex353.

The multiplexing/demultiplexing unit ex353 multiplexes the coded videodata supplied from the video signal processing unit ex355 and the codedaudio data supplied from the audio signal processing unit ex354, using apredetermined method. Then, the modulation/demodulation unit(modulation/demodulation circuit unit) ex352 performs spread spectrumprocessing on the multiplexed data, and the transmitting and receivingunit ex351 performs digital-to-analog conversion and frequencyconversion on the data so as to transmit the resulting data via theantenna ex350.

When receiving data of a video file which is linked to a Web page andothers in data communication mode or when receiving an e-mail with videoand/or audio attached, in order to decode the multiplexed data receivedvia the antenna ex350, the multiplexing/demultiplexing unit ex353demultiplexes the multiplexed data into a video data bit stream and anaudio data bit stream, and supplies the video signal processing unitex355 with the coded video data and the audio signal processing unitex354 with the coded audio data, through the synchronous bus ex370. Thevideo signal processing unit ex355 decodes the video signal using amoving picture decoding method corresponding to the moving picturecoding method shown in each of Embodiments (i.e., functions as the imagedecoding apparatus of the present invention), and then the display unitex358 displays, for instance, the video and still images included in thevideo file linked to the Web page via the LCD control unit ex359.Furthermore, the audio signal processing unit ex354 decodes the audiosignal, and the audio output unit ex357 provides the audio.

Furthermore, similarly to the television ex300, a terminal such as thecellular phone ex114 probably have 3 types of implementationconfigurations including not only (i) a transmitting and receivingterminal including both a coding apparatus and a decoding apparatus, butalso (ii) a transmitting terminal including only a coding apparatus and(iii) a receiving terminal including only a decoding apparatus. Althoughthe digital broadcasting system ex200 receives and transmits themultiplexed data obtained by multiplexing audio data onto video data inthe description, the multiplexed data may be data obtained bymultiplexing not audio data but character data related to video ontovideo data, and may be not multiplexed data but video data itself.

As such, the moving picture coding method and the moving picturedecoding method in each of Embodiments can be used in any of the devicesand systems described. Thus, the advantages described in each ofEmbodiments can be obtained.

Furthermore, the present invention is not limited to Embodiments, andvarious modifications and revisions are possible without departing fromthe scope of the present invention.

Embodiment 7

Video data can be generated by switching, as necessary, between (i) themoving picture coding method or the moving picture coding apparatusshown in each of Embodiments and (ii) a moving picture coding method ora moving picture coding apparatus in conformity with a differentstandard, such as MPEG-2, MPEG4-AVC, and VC-1.

Here, when a plurality of video data that conforms to the differentstandards is generated and is then decoded, the decoding methods need tobe selected to conform to the different standards. However, since towhich standard each of the plurality of the video data to be decodedconform cannot be detected, there is a problem that an appropriatedecoding method cannot be selected.

In order to solve the problem, multiplexed data obtained by multiplexingaudio data and others onto video data has a structure includingidentification information indicating to which standard the video dataconforms. The specific structure of the multiplexed data including thevideo data generated in the moving picture coding method and by themoving picture coding apparatus shown in each of Embodiments will behereinafter described. The multiplexed data is a digital stream in theMPEG2-Transport Stream format.

FIG. 22 illustrates a structure of the multiplexed data. As illustratedin FIG. 22, the multiplexed data can be obtained by multiplexing atleast one of a video stream, an audio stream, a presentation graphicsstream (PG), and an interactive graphics stream. The video streamrepresents primary video and secondary video of a movie, the audiostream (IG) represents a primary audio part and a secondary audio partto be mixed with the primary audio part, and the presentation graphicsstream represents subtitles of the movie. Here, the primary video isnormal video to be displayed on a screen, and the secondary video isvideo to be displayed on a smaller window in the primary video.Furthermore, the interactive graphics stream represents an interactivescreen to be generated by arranging the GUI components on a screen. Thevideo stream is coded in the moving picture coding method or by themoving picture coding apparatus shown in each of Embodiments, or in amoving picture coding method or by a moving picture coding apparatus inconformity with a conventional standard, such as MPEG-2, MPEG4-AVC, andVC-1. The audio stream is coded in accordance with a standard, such asDolby-AC-3, Dolby Digital Plus, MLP, DTS, DTS-HD, and linear PCM.

Each stream included in the multiplexed data is identified by PID. Forexample, 0x1011 is allocated to the video stream to be used for video ofa movie, 0x1100 to 0x111F are allocated to the audio streams, 0x1200 to0x121F are allocated to the presentation graphics streams, 0x1400 to0x141F are allocated to the interactive graphics streams, 0x1B00 to0x1B1F are allocated to the video streams to be used for secondary videoof the movie, and 0x1A00 to 0x1A1F are allocated to the audio streams tobe used for the secondary video to be mixed with the primary audio.

FIG. 23 schematically illustrates how data is multiplexed. First, avideo stream ex235 composed of video frames and an audio stream ex238composed of audio frames are transformed into a stream of PES packetsex236 and a stream of PES packets ex239, and further into TS packetsex237 and TS packets ex240, respectively. Similarly, data of apresentation graphics stream ex241 and data of an interactive graphicsstream ex244 are transformed into a stream of PES packets ex242 and astream of PES packets ex245, and further into TS packets ex243 and TSpackets ex246, respectively. These TS packets are multiplexed into astream to obtain multiplexed data ex247.

FIG. 24 illustrates how a video stream is stored in a stream of PESpackets in more detail. The first bar in FIG. 24 shows a video framestream in a video stream. The second bar shows the stream of PESpackets. As indicated by arrows denoted as yy1, yy2, yy3, and yy4 inFIG. 24, the video stream is divided into pictures as I pictures, Bpictures, and P pictures each of which is a video presentation unit, andthe pictures are stored in a payload of each of the PES packets. Each ofthe PES packets has a PES header, and the PES header stores aPresentation Time-Stamp (PTS) indicating a display time of the picture,and a Decoding Time-Stamp (DTS) indicating a decoding time of thepicture.

FIG. 25 illustrates a format of TS packets to be finally written on themultiplexed data. Each of the TS packets is a 188-byte fixed lengthpacket including a 4-byte TS header having information, such as a PIDfor identifying a stream and a 184-byte TS payload for storing data. ThePES packets are divided, and stored in the TS payloads, respectively.When a BD ROM is used, each of the TS packets is given a 4-byteTP_Extra_Header, thus resulting in 192-byte source packets. The sourcepackets are written on the multiplexed data. The TP_Extra_Header storesinformation such as an Arrival_Time_Stamp (ATS). The ATS shows atransfer start time at which each of the TS packets is to be transferredto a PID filter. The source packets are arranged in the multiplexed dataas shown at the bottom of FIG. 25. The numbers incrementing from thehead of the multiplexed data are called source packet numbers (SPNs).

Each of the TS packets included in the multiplexed data includes notonly streams of audio, video, subtitles and others, but also a ProgramAssociation Table (PAT), a Program Map Table (PMT), and a Program ClockReference (PCR). The PAT shows what a PID in a PMT used in themultiplexed data indicates, and a PID of the PAT itself is registered aszero. The PMT stores PIDs of the streams of video, audio, subtitles andothers included in the multiplexed data, and attribute information ofthe streams corresponding to the PIDs. The PMT also has variousdescriptors relating to the multiplexed data. The descriptors haveinformation such as copy control information showing whether copying ofthe multiplexed data is permitted or not. The PCR stores STC timeinformation corresponding to an ATS showing when the PCR packet istransferred to a decoder, in order to achieve synchronization between anArrival Time Clock (ATC) that is a time axis of ATSs, and an System TimeClock (STC) that is a time axis of PTSs and DTSs.

FIG. 26 illustrates the data structure of the PMT in detail. A PMTheader is disposed at the top of the PMT. The PMT header describes thelength of data included in the PMT and others. A plurality ofdescriptors relating to the multiplexed data is disposed after the PMTheader. Information such as the copy control information is described inthe descriptors. After the descriptors, a plurality of pieces of streaminformation relating to the streams included in the multiplexed data isdisposed. Each piece of stream information includes stream descriptorseach describing information, such as a stream type for identifying acompression codec of a stream, a stream PID, and stream attributeinformation (such as a frame rate or an aspect ratio). The streamdescriptors are equal in number to the number of streams in themultiplexed data.

When the multiplexed data is recorded on a recording medium and others,it is recorded together with multiplexed data information files.

Each of the multiplexed data information files is management informationof the multiplexed data as shown in FIG. 27. The multiplexed datainformation files are in one to one correspondence with the multiplexeddata, and each of the files includes multiplexed data information,stream attribute information, and an entry map.

As illustrated in FIG. 27, the multiplexed data includes a system rate,a reproduction start time, and a reproduction end time. The system rateindicates the maximum transfer rate at which a system target decoder tobe described later transfers the multiplexed data to a PID filter. Theintervals of the ATSs included in the multiplexed data are set to nothigher than a system rate. The reproduction start time indicates a PTSin a video frame at the head of the multiplexed data. An interval of oneframe is added to a PTS in a video frame at the end of the multiplexeddata, and the PTS is set to the reproduction end time.

As shown in FIG. 28, a piece of attribute information is registered inthe stream attribute information, for each PID of each stream includedin the multiplexed data. Each piece of attribute information hasdifferent information depending on whether the corresponding stream is avideo stream, an audio stream, a presentation graphics stream, or aninteractive graphics stream. Each piece of video stream attributeinformation carries information including what kind of compression codecis used for compressing the video stream, and the resolution, aspectratio and frame rate of the pieces of picture data that is included inthe video stream. Each piece of audio stream attribute informationcarries information including what kind of compression codec is used forcompressing the audio stream, how many channels are included in theaudio stream, which language the audio stream supports, and how high thesampling frequency is. The video stream attribute information and theaudio stream attribute information are used for initialization of adecoder before the player plays back the information.

In the present embodiment, the multiplexed data to be used is of astream type included in the PMT. Furthermore, when the multiplexed datais recorded on a recording medium, the video stream attributeinformation included in the multiplexed data information is used. Morespecifically, the moving picture coding method or the moving picturecoding apparatus described in each of Embodiments includes a step or aunit for allocating unique information indicating video data generatedby the moving picture coding method or the moving picture codingapparatus in each of Embodiments, to the stream type included in the PMTor the video stream attribute information. With the configuration, thevideo data generated by the moving picture coding method or the movingpicture coding apparatus described in each of Embodiments can bedistinguished from video data that conforms to another standard.

Furthermore, FIG. 29 illustrates steps of the moving picture decodingmethod according to the present embodiment. In Step exS100, the streamtype included in the PMT or the video stream attribute information isobtained from the multiplexed data. Next, in Step exS101, it isdetermined whether or not the stream type or the video stream attributeinformation indicates that the multiplexed data is generated by themoving picture coding method or the moving picture coding apparatus ineach of Embodiments. When it is determined that the stream type or thevideo stream attribute information indicates that the multiplexed datais generated by the moving picture coding method or the moving picturecoding apparatus in each of Embodiments, in Step exS102, decoding isperformed by the moving picture decoding method in each of Embodiments.Furthermore, when the stream type or the video stream attributeinformation indicates conformance to the conventional standards, such asMPEG-2, MPEG4-AVC, and VC-1, in Step exS103, decoding is performed by amoving picture decoding method in conformity with the conventionalstandards.

As such, allocating a new unique value to the stream type or the videostream attribute information enables determination whether or not themoving picture decoding method or the moving picture decoding apparatusthat is described in each of Embodiments can perform decoding. Even whenmultiplexed data that conforms to a different standard, an appropriatedecoding method or apparatus can be selected. Thus, it becomes possibleto decode information without any error. Furthermore, the moving picturecoding method or apparatus, or the moving picture decoding method orapparatus in the present embodiment can be used in the devices andsystems described above.

Embodiment 8

Each of the moving picture coding method, the moving picture codingapparatus, the moving picture decoding method, and the moving picturedecoding apparatus in each of Embodiments is typically achieved in theform of an integrated circuit or a Large Scale Integrated (LSI) circuit.As an example of the LSI, FIG. 30 illustrates a configuration of the LSIex500 that is made into one chip. The LSI ex500 includes elements ex501,ex502, ex503, ex504, ex505, ex506, ex507, ex508, and ex509 to bedescribed below, and the elements are connected to each other through abus ex510. The power supply circuit unit ex505 is activated by supplyingeach of the elements with power when the power supply circuit unit ex505is turned on.

For example, when coding is performed, the LSI ex500 receives an AVsignal from a microphone ex117, a camera ex113, and others through an AVIO ex509 under control of a control unit ex501 including a CPU ex502, amemory controller ex503, a stream controller ex504, and a drivingfrequency control unit ex512. The received AV signal is temporarilystored in an external memory ex511, such as an SDRAM. Under control ofthe control unit ex501, the stored data is segmented into data portionsaccording to the processing amount and speed to be transmitted to asignal processing unit ex507. Then, the signal processing unit ex507codes an audio signal and/or a video signal. Here, the coding of thevideo signal is the coding described in each of Embodiments.Furthermore, the signal processing unit ex507 sometimes multiplexes thecoded audio data and the coded video data, and a stream IO ex506provides the multiplexed data outside. The provided multiplexed data istransmitted to the base station ex107, or written on the recording mediaex215. When data sets are multiplexed, the data should be temporarilystored in the buffer ex508 so that the data sets are synchronized witheach other.

Although the memory ex511 is an element outside the LSI ex500, it may beincluded in the LSI ex500. The buffer ex508 is not limited to onebuffer, but may be composed of buffers. Furthermore, the LSI ex500 maybe made into one chip or a plurality of chips.

Furthermore, although the control unit ex501 includes the CPU ex502, thememory controller ex503, the stream controller ex504, the drivingfrequency control unit ex512, the configuration of the control unitex501 is not limited to such. For example, the signal processing unitex507 may further include a CPU. Inclusion of another CPU in the signalprocessing unit ex507 can improve the processing speed. Furthermore, asanother example, the CPU ex502 may serve as or be a part of the signalprocessing unit ex507, and, for example, may include an audio signalprocessing unit. In such a case, the control unit ex501 includes thesignal processing unit ex507 or the CPU ex502 including a part of thesignal processing unit ex507.

The name used here is LSI, but it may also be called IC, system LSI,super LSI, or ultra LSI depending on the degree of integration.

Moreover, ways to achieve integration are not limited to the LSI, and aspecial circuit or a general purpose processor and so forth can alsoachieve the integration. Field Programmable Gate Array (FPGA) that canbe programmed after manufacturing LSIs or a reconfigurable processorthat allows re-configuration of the connection or configuration of anLSI can be used for the same purpose.

In the future, with advancement in semiconductor technology, a brand-newtechnology may replace LSI. The functional blocks can be integratedusing such a technology. The possibility is that the present inventionis applied to biotechnology.

Embodiment 9

When video data generated in the moving picture coding method or by themoving picture coding apparatus described in each of Embodiments isdecoded, compared to when video data that conforms to a conventionalstandard, such as MPEG-2, MPEG4-AVC, and VC-1 is decoded, the processingamount probably increases. Thus, the LSI ex500 needs to be set to adriving frequency higher than that of the CPU ex502 to be used whenvideo data in conformity with the conventional standard is decoded.However, when the driving frequency is set higher, there is a problemthat the power consumption increases.

In order to solve the problem, the moving picture decoding apparatus,such as the television ex300 and the LSI ex500 is configured todetermine to which standard the video data conforms, and switch betweenthe driving frequencies according to the determined standard. FIG. 31illustrates a configuration ex800 in the present embodiment. A drivingfrequency switching unit ex803 sets a driving frequency to a higherdriving frequency when video data is generated by the moving picturecoding method or the moving picture coding apparatus described in eachof Embodiments. Then, the driving frequency switching unit ex803instructs a decoding processing unit ex801 that executes the movingpicture decoding method described in each of Embodiments to decode thevideo data. When the video data conforms to the conventional standard,the driving frequency switching unit ex803 sets a driving frequency to alower driving frequency than that of the video data generated by themoving picture coding method or the moving picture coding apparatusdescribed in each of Embodiments. Then, the driving frequency switchingunit ex803 instructs the decoding processing unit ex802 that conforms tothe conventional standard to decode the video data.

More specifically, the driving frequency switching unit ex803 includesthe CPU ex502 and the driving frequency control unit ex512 in FIG. 30.Here, each of the decoding processing unit ex801 that executes themoving picture decoding method described in each of Embodiments and thedecoding processing unit ex802 that conforms to the conventionalstandard corresponds to the signal processing unit ex507 in FIG. 30. TheCPU ex502 determines to which standard the video data conforms. Then,the driving frequency control unit ex512 determines a driving frequencybased on a signal from the CPU ex502. Furthermore, the signal processingunit ex507 decodes the video data based on the signal from the CPUex502. For example, the identification information described inEmbodiment 7 is probably used for identifying the video data. Theidentification information is not limited to the one described inEmbodiment 7 but may be any information as long as the informationindicates to which standard the video data conforms. For example, whenwhich standard video data conforms to can be determined based on anexternal signal for determining that the video data is used for atelevision or a disk, etc., the determination may be made based on suchan external signal. Furthermore, the CPU ex502 selects a drivingfrequency based on, for example, a look-up table in which the standardsof the video data are associated with the driving frequencies as shownin FIG. 33. The driving frequency can be selected by storing the look-uptable in the buffer ex508 and in an internal memory of an LSI, and withreference to the look-up table by the CPU ex502.

FIG. 32 illustrates steps for executing a method in the presentembodiment. First, in Step exS200, the signal processing unit ex507obtains identification information from the multiplexed data. Next, inStep exS201, the CPU ex502 determines whether or not the video data isgenerated by the coding method and the coding apparatus described ineach of Embodiments, based on the identification information. When thevideo data is generated by the moving picture coding method and themoving picture coding apparatus described in each of Embodiments, inStep exS202, the CPU ex502 transmits a signal for setting the drivingfrequency to a higher driving frequency to the driving frequency controlunit ex512. Then, the driving frequency control unit ex512 sets thedriving frequency to the higher driving frequency. On the other hand,when the identification information indicates that the video dataconforms to the conventional standard, such as MPEG-2, MPEG4-AVC, andVC-1, in Step exS203, the CPU ex502 transmits a signal for setting thedriving frequency to a lower driving frequency to the driving frequencycontrol unit ex512. Then, the driving frequency control unit ex512 setsthe driving frequency to the lower driving frequency than that in thecase where the video data is generated by the moving picture codingmethod and the moving picture coding apparatus described in each ofEmbodiment.

Furthermore, along with the switching of the driving frequencies, thepower conservation effect can be improved by changing the voltage to beapplied to the LSI ex500 or an apparatus including the LSI ex500. Forexample, when the driving frequency is set lower, the voltage to beapplied to the LSI ex500 or the apparatus including the LSI ex500 isprobably set to a voltage lower than that in the case where the drivingfrequency is set higher.

Furthermore, when the processing amount for decoding is larger, thedriving frequency may be set higher, and when the processing amount fordecoding is smaller, the driving frequency may be set lower as themethod for setting the driving frequency. Thus, the setting method isnot limited to the ones described above. For example, when theprocessing amount for decoding video data in conformity with MPEG 4-AVCis larger than the processing amount for decoding video data generatedby the moving picture coding method and the moving picture codingapparatus described in each of Embodiments, the driving frequency isprobably set in reverse order to the setting described above.

Furthermore, the method for setting the driving frequency is not limitedto the method for setting the driving frequency lower. For example, whenthe identification information indicates that the video data isgenerated by the moving picture coding method and the moving picturecoding apparatus described in each of Embodiments, the voltage to beapplied to the LSI ex500 or the apparatus including the LSI ex500 isprobably set higher. When the identification information indicates thatthe video data conforms to the conventional standard, such as MPEG-2,MPEG4-AVC, and VC-1, the voltage to be applied to the LSI ex500 or theapparatus including the LSI ex500 is probably set lower. As anotherexample, when the identification information indicates that the videodata is generated by the moving picture coding method and the movingpicture coding apparatus described in each of Embodiments, the drivingof the CPU ex502 does not probably have to be suspended. When theidentification information indicates that the video data conforms to theconventional standard, such as MPEG-2, MPEG4-AVC, and VC-1, the drivingof the CPU ex502 is probably suspended at a given time because the CPUex502 has extra processing capacity. Even when the identificationinformation indicates that the video data is generated by the movingpicture coding method and the moving picture coding apparatus describedin each of Embodiments, in the case where the CPU ex502 has extraprocessing capacity, the driving of the CPU ex502 is probably suspendedat a given time. In such a case, the suspending time is probably setshorter than that in the case where when the identification informationindicates that the video data conforms to the conventional standard,such as MPEG-2, MPEG4-AVC, and VC-1.

Accordingly, the power conservation effect can be improved by switchingbetween the driving frequencies in accordance with the standard to whichthe video data conforms. Furthermore, when the LSI ex500 or theapparatus including the LSI ex500 is driven using a battery, the batterylife can be extended with the power conservation effect.

Embodiment 10

There are cases where a plurality of video data that conforms todifferent standards, is provided to the devices and systems, such as atelevision and a mobile phone. In order to enable decoding the pluralityof video data that conforms to the different standards, the signalprocessing unit ex507 of the LSI ex500 needs to conform to the differentstandards. However, the problems of increase in the scale of the circuitof the LSI ex500 and increase in the cost arise with the individual useof the signal processing units ex507 that conform to the respectivestandards.

In order to solve the problem, what is conceived is a configuration inwhich the decoding processing unit for implementing the moving picturedecoding method described in each of Embodiments and the decodingprocessing unit that conforms to the conventional standard, such asMPEG-2, MPEG4-AVC, and VC-1 are partly shared. Ex900 in FIG. 34A showsan example of the configuration. For example, the moving picturedecoding method described in each of Embodiments and the moving picturedecoding method that conforms to MPEG4-AVC have, partly in common, thedetails of processing, such as entropy coding, inverse quantization,deblocking filtering, and motion compensated prediction. The details ofprocessing to be shared probably include use of a decoding processingunit ex902 that conforms to MPEG4-AVC. In contrast, a dedicated decodingprocessing unit ex901 is probably used for other processing unique tothe present invention. Since the present invention is characterized bypulse code modulation in particular, for example, the dedicated decodingprocessing unit ex901 is used for pulse code modulation. Otherwise, thedecoding processing unit is probably shared for one of the entropycoding, inverse quantization, deblocking filtering, and motioncompensation, or all of the processing. The decoding processing unit forimplementing the moving picture decoding method described in each ofEmbodiments may be shared for the processing to be shared, and adedicated decoding processing unit may be used for processing unique tothat of MPEG4-AVC.

Furthermore, ex1000 in FIG. 34B shows another example in that processingis partly shared. This example uses a configuration including adedicated decoding processing unit ex1001 that supports the processingunique to the present invention, a dedicated decoding processing unitex1002 that supports the processing unique to another conventionalstandard, and a decoding processing unit ex1003 that supports processingto be shared between the moving picture decoding method in the presentinvention and the conventional moving picture decoding method. Here, thededicated decoding processing units ex1001 and ex1002 are notnecessarily specialized for the processing of the present invention andthe processing of the conventional standard, respectively, and may bethe ones capable of implementing general processing. Furthermore, theconfiguration of the present embodiment can be implemented by the LSIex500.

As such, reducing the scale of the circuit of an LSI and reducing thecost are possible by sharing the decoding processing unit for theprocessing to be shared between the moving picture decoding method inthe present invention and the moving picture decoding method inconformity with the conventional standard.

INDUSTRIAL APPLICABILITY

The image coding method and the image decoding method according to thepresent disclosure can be applied to various kinds of multimedia data toimprove coding efficiency. For example, the image coding method and theimage decoding method according to the present disclosure are useful formobile telephones, DVD apparatuses, personal computers, and the like.

1-10. (canceled)
 11. An image coding method of coding images to generatea coded stream, the image coding method comprising: writing a firstparameter into a sequence parameter set in the coded stream to begenerated, the first parameter representing a first bit-depth that is abit-depth of a reconstructed sample in the images; writing a secondparameter different from the first parameter into the sequence parameterset, the second parameter representing a second bit-depth that is abit-depth of an Intra Pulse Code Modulation (IPCM) luma sample in theimages; and writing a third parameter different from both of the firstparameter and the second parameter into the sequence parameter set, thethird parameter representing a third bit-depth that is a bit-depth of anIPCM chroma sample in the image.